Big Rich

Any Ideas

Here is what started happening:

freeway speeds
overdrive engaged

started shifting between OD and 3rd

now no OD

Shifts fine in all gears except OD, just as if OD disengaged

Help

Rich

apache

sounds like the throttle position sensor has gone out of adjustment or bad. Do a search in the tech section to find how to fix or adjust. its easy doins.

Mcmopar

That year was all hydraulic except for the OD on/off, mabye the switch went bad??

Forrest Nearing

my '91 had a TPS and the same thing happened to it.

Dan Brooks

Besides a bad TPS, a faulty trans temp "switch" (the sending unit on the trans line) can cause OD problems.

The first thing I'd try is cleaning and packing the TPS, temp switch, and speed sensor connections with dielectric grease. That took care of my problems for quite a while, but now it looks like my temp switch is bad.

Den

Had the same problem with my 91.5 recently. I dropped the pan, changed the filter and added new fliud. Overdrive is back again.

When OD did stop working it, it stopped all of the sudden and then didn't engage anymore at all. The first drive after the service it kicked right back in again

Good luck

Den

Big Rich

Heading out to work on the 1st gen right now. Plan is to do all the electrical items suggested, and if that does not work, then have the trans filter and fluid changed. Though the fluid smells and looks good.

Thanks
Rich

Big Rich

Tested voltage and only read 0.38v, tried to adjust and clean and got to 0.51v. Looks like it's time for a new TPS

Thanks

Rich